Introduction:
It is a long time that natural toxin research is conducted to unlock the medical
potential of toxins. Although venoms-toxins cause pathophysiological conditions, they
may be effective to treat several diseases. Since toxins including scorpion toxins
target voltage-gated ion channels, they may have profound effects on excitable cells.
Therefore, elucidating the cellular and electrophysiological impacts of toxins,
particularly scorpion toxins would be helpful in future drug development
opportunities.
Methods:
Intracellular recording was made from F1 cells of Helix aspersa in the presence of
calcium Ringer solution in which Na
+
and K
+
channels were blocked. Then, the modulation of channel function in the presence of
extracellular application of F4 and F6 toxins and kaliotoxin (KTX; 50 nM and 1
μM) was examined by assessing the electrophysiological characteristics of
calcium spikes.
Results:
The two active toxin fractions, similar to KTX, a known
Ca
2+
-activated K
+
channel blocker, reduced the
amplitude of AHP, enhanced the firing frequency of calcium spikes and broadened the
duration of Ca
2+
spikes. Therefore, it might be inferred that these
two new fractions induce neuronal hyperexcitability possibly, in part, by blocking
calcium-activated potassium channel current. However, this supposition requires further
investigation using voltage clamping technique.
Conclusion:
These toxin fractions may act as blocker of calcium-activated potassium channels.